import java.util.*;
public class palindrome {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		Scanner kb = new Scanner(System.in);
		String phrase = kb.nextLine();
		Boolean isPal = isPalindrome(phrase);
		System.out.println(isPal);
		
		
		System.out.println("Dicks");

	}

	
	
	
	public static Boolean isPalindrome(String phrase){
		phrase = phrase.replaceAll("\\s", "");
		System.out.println(phrase);
		if (phrase.length() % 2 == 0){
			System.out.println("ONPOSSIBLE");
			return false;
		}
		
		int count = 0, count2 = phrase.length() - 1;
		while (count < count2) {
			if (phrase.charAt(count) != phrase.charAt(count2)) {
				return false;
			}
			count++;
			count2--;
				
		}
		return true;
	}
}
